AllChemicals — The Online Chemical Glossary | https://allchemicals.info/chemical/412-excited-state
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Quick Reference
Also Known As
Electronic excited state, excited level, upper state (spectroscopy)
What is Excited State?
An energy state of an atom, ion, or molecule that is higher than its ground state. Electrons in excited states occupy higher energy orbitals. When electrons return to lower energy levels, they emit photons of specific wavelengths, producing characteristic emission spectra.
Properties & Characteristics
An excited state is a quantum state of an atom, molecule, or nucleus in which the system has absorbed energy and is at a higher energy level than the ground state. Electronic excited states result from UV-Vis photon absorption (π→π*, n→π* transitions); vibrational and rotational excited states absorb IR and microwave radiation. Excited states have short lifetimes and decay by emitting photons (fluorescence, phosphorescence) or by non-radiative relaxation.
Uses & Applications
Excited states are fundamental to: spectroscopy (UV-Vis, IR, Raman, fluorescence), laser operation (stimulated emission from population-inverted excited states), photosynthesis (excited chlorophyll molecules drive electron transfer), photochemistry (excited state reactivity differs from ground state), and fluorescent labels in biochemistry.
Safety Information
Excited state molecules may react differently and more readily than ground state molecules, potentially generating reactive intermediates (singlet oxygen, radicals). UV photons creating excited states in skin biomolecules can cause DNA damage and sunburn. Photosensitisers that generate long-lived excited triplet states used in PDT can cause tissue damage.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
SynonymsElectronic excited state, excited level, upper state (spectroscopy)
Frequently Asked Questions
An energy state of an atom, ion, or molecule that is higher than its ground state. Electrons in excited states occupy higher energy orbitals. When electrons return to lower energy levels, they emit photons of specific wavelengths, producing characteristic emission spectra.
Excited states are fundamental to: spectroscopy (UV-Vis, IR, Raman, fluorescence), laser operation (stimulated emission from population-inverted excited states), photosynthesis (excited chlorophyll molecules drive electron transfer), photochemistry (excited state reactivity differs from ground state…
Excited state molecules may react differently and more readily than ground state molecules, potentially generating reactive intermediates (singlet oxygen, radicals). UV photons creating excited states in skin biomolecules can cause DNA damage and sunburn. Photosensitisers that generate long-lived ex…
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CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA,
and IAEA. For educational purposes only — always consult official SDS documentation and qualified
professionals before handling chemicals.
